In a discrete-trial conditional discrimination procedure, 4 pigeons obtained food reinforcers by pecking a key with a short latency on trials signaled by one stimulus and by pecking the same key with a long latency on trials signaled by a second stimulus. The physical difference between the two stimuli and ...

Four pigeons responded in components of multiple schedules in which two responses were available and reinforced with food. Pecks on the left key ("main" key) were reinforced at a constant rate in one component and at a rate that varied over conditions in the other component. When reinforcer rate was ...

Six pigeons responded on two concurrently available keys that defined patches with the following characteristics. Reinforcer stores repleted on a patch as a linear function of time when the bird had last responded to the other patch, or else did not replete. Repletion schedules thus timed only when the bird ...

Rats' presses on one lever canceled shocks programmed after variable cycles, while presses on a second lever occasionally produced a 2-min timout during which the shock-delection schedule was suspended and its correlated stimuli removed. These concurrent schedules of avoidance and timeout were embedded in a multiple schedule whose components differed, ...

In two experiments, key pecking of pigeons was maintained by a variable-interval 180-s schedule of food presentation. Conjointly, a second schedule delivered response-dependent electric shock. In the first experiment, shocks were presented according to either a variable-interval or a nondifferential interval-percentile schedule. The variable-interval shock schedule differentially delivered shocks following ...

Rats responded under progressive-ratio schedules for sweetened milk reinforcers; each session ended when responding ceased for 10 min. Experiment 1 varied the concentration of milk and the duration of postreinforcement timeouts. Postreinforcement pausing increased as a positively accelerated function of the size of the ratio, and the rate of increase ...

Procedures used to study anticipatory contrast are conceptually similar to those used to study autoshaping, in that two target stimuli signal either higher or lower rates of reinforcement in the following components of the schedule. Despite this signal contingency, anticipatory contrast entails response rates that are higher to the target ...

Six experimentally naive pigeons were exposed to concurrent variable-interval variable-interval schedules in a three-key procedure in which food reinforcement followed pecks on the side keys and pecks on the center key served as changeover responses. In Phase 1, 3 birds were exposed to 20 combinations of five variable-interval values, with ...

In Experiment 1, two conditions were compared: (a) a variability schedule in which food reinforcement was delivered for the fourth peck in a sequence that differed from the preceding N four-peck sequences, with the value of N continuously adjusted to maintain reinforcement probability approximately constant; and (b) a control condition ...

Two pigeons had access to multiple concurrent schedules of reinforcement for 24 hours per day in their home cages. The variable-interval schedules comprising the multiple concurrent schedules were varied across 16 conditions. In three sets of conditions, one schedule was varied while its concurrent alternative and the concurrent schedules in ...

Pigeons were exposed to delayed-matching-to-sample (DMTS) procedures in which food or a flash of the feeder light followed correct responses. When these consequences were correlated with a particular stimulus (e.g., food followed matching responses to red and a flash of the feeder light followed matching responses to green), accuracy was ...

This study demonstrates that individual animals can concurrently acquire differently timed conditioned eyelid responses using a differential conditioning procedure in which distinctive conditioned stimuli (CSs) are individually paired with an unconditioned stimulus, with each using a different interstimulus interval (ISI). This promotes robust conditioning, and the timing of the conditioned ...

Pigeons chose between two fixed-interval schedules of food reinforcement. A single peck on one of two lighted keys started the fixed-interval schedule correlated with that key. The schedule had to be completed before the next choice opportunity. The durations of the fixed intervals were varied over conditions from 15 s ...

The comparator hypothesis is a response rule stating that responding to a Pavlovian conditioned stimulus (CS) reflects the associative strength of the CS relative to that of other cues (comparator stimuli) that were present during CS training. Thus, modulation of the associative strength of a CS's comparator stimulus should alter ...

An approach to reinforcement-schedule contingencies is presented that accommodates continuous as well as discrete effective dimensions of responses and reinforcers. College students' wheel turning was reinforced by projected reading material according to four schedule contingencies that incorporated either a discontinuous (count) or continuous (duration) dimension of the response and the ...

Five pigeons were trained in a delayed matching-to-sample task with red and green stimuli. The retention interval between sample-stimulus presentation and the availability of the choice stimuli was varied between 0.01 s and 12 s within each session. The probability of food produced by correct-red and correct-green responses was varied ...

Behavioral momentum is the product of response rate and resistance to change. The data on relative resistance to change are summarized for pigeons responding on single-key two-component multiple schedules, in the initial links of two-key multiple chained schedules, and in equivalent components of two-key serial schedules. For single-key procedures, the ...

Three experiments using multiple schedules of reinforcement explored the implications of resistance-to-change findings for the response-reinforcer relation described by the law of effect, using both steady-state responding and responding recorded in the first few sessions of conditions. In Experiment 1, when response-independent reinforcement was increased during a third component, response ...

The dynamics of the performance of an instrumental task by Macaca rhesus monkeys was investigated in an automated experiment. Three monkeys were trained to complete a movement with a lever in response to a light stimulus. It was demonstrated that the performance of the instrumental reflex by the monkeys is ...

The present study investigated the effects of the dopamine (DA) D1 selective agonist, SKF 38393, and the D2 selective agonists, quinpirole and bromocriptine, on responding for conditioned reward. The nonselective DA agonist apomorphine and the indirect agonist amphetamine, were also evaluated. Male rats (n = 302) were tested in a ...

We developed a video system for real-time detection of a pigeon's orientation and for reinforcement of a "turning response." Using this system, negative behavioral contrast was found across key-peck and turning responses. In addition, turning away from the pecking key was detected by the system just after presentation of the ...

Pigeons acquired discriminated key pecking between 528- and 540-nm stimuli by either a response-reinforcer (operant group) or a stimulus-reinforcer (autoshaped group) contingency, with other training-schedule parameters comparable over groups. For the birds in the operant group, key pecks intermittently produced grain in the presence of one hue on the key ...

The present investigations sought to determine the effects of 3,4-methylenedioxyamphetamine (MDA) on: 1) differential conditioning of the rabbit's nictitating membrane response to the serial compounds A-X-US (tone-light-reinforced compound) and B-X (white noise-light-unreinforced compound) by examining differential responding to A and B and their conditional control over responding to X within ...

The aim of this study was to determine whether reinforcer-specific conditioned responding would occur in a situation in which responding was not thought to be mediated by a representation that encodes information about the specific properties of the reinforcer. The force of the pigeon's keypeck was monitored during first- and ...

A mild electrical shock delivered to the walking legs of the crab Chasmagnathus granulatus through a fine layer of sea water, induces a running response that declines after repeated stimulation. Herein, a first series of experiments was aimed at conditioning the response to a light or a dark pulse, but ...

Pigeons responded on fixed-ratio schedules ending in small or large reinforcers (grain presentations of different duration) interspersed within each session. In mixed-schedule conditions, the response key was lit with a single color throughout the session, and pausing was directly related to the past reinforcer (longer pauses after large reinforcers than ...

Six pigeons were trained to discriminate between two intensities of white light in a symbolic matching-to-sample procedure. These stimuli were then used to signal which schedule was available on the main key in a switching-key concurrent schedule. The concurrent schedules led to a symbolic matching-to-sample phase in which the subject ...

Pigeons pecked at one of two black forms, "+" or "O," either of which could appear alone on a white computer monitor screen. In baseline series of sessions, each form appeared equally often, and two pecks at it produced food reinforcement on 10% of trials. Test series varied the relative ...

Pigeons' ability to discriminate stimulus duration, focusing on stimuli less than 1 s in duration, was evaluated in 4 experiments. In Experiment 1, the performances of pigeons and humans were compared with a staircase technique, and in Experiment 2, the method of constant stimuli was used. Both experiments produced similar ...

Pigeons were exposed to two different reinforcement schedules under different stimulus conditions in each of two daily sessions separated by 6 hr (Experiments 1 and 2) or in a single session (Experiment 3). Following this, either a fixed-interval (Experiment 1) or a variable-interval schedule (Experiments 2 and 3) was effected ...

In Experiment 1, subjects acquired conditional equivalence classes controlled by three male and three female names as contextual stimuli. When equivalence relations were tested using new names not used in training (three male and three female), contextual control remained intact. Thus, generalized control of the composition of conditional equivalence classes ...

Previous research on humans suggests that simple discriminations may emerge if both stimuli, B1 and B2, are compounded with the stimuli of a previously trained discrimination, A1 (S+) and A2 (S-), and responding to the compounds, B1A1 and B2A2, is reinforced. Two questions were addressed. First, do simple discriminations also ...

An attempt was made to train pigeons to discriminate phencyclidine (PCP) from saline using a three-key color-tracking procedure under which birds were trained under a second order schedule [FR10 (FR5)] "without errors." Training without errors was done by not lighting the side key on which responses were not reinforced during ...

The eyes of the pigeon (Columba livia) are positioned laterally in the head. Thus, there is only a small area of binocular overlap, which constitutes the frontal visual field and a large area of monocular vision in the lateral visual fields. The conditions were examined under which intraocular transfer occurs ...

The behavioral effects of haloperidol (0.04 to 0.16 mg/kg) and nonparalytic doses of decamethonium (0.2 to 0.8 mg/kg) were studied with operant methods that permitted the measurement of response rate, peak force of response, duration of response, and duration of the rat's head entry into the reinforcement dipper well. Type ...

Since Pavlov, theories of conditioning have assumed that CR evocation is governed by a series of internal stimuli generated by the CS. This hypothesis was tested in conditioning of the rabbit's nictitating membrane (NM) response by attempting to manipulate the internal sequence through truncating a delay CS and extending a ...

The dynamics of the changes in the number of instrumental motor reactions and in the frequency of cardiac contractions and of the theta rhythm of the hippocampus during the replacement of constant reinforcement by various schedules of probabilistic reinforcement of an alimentary conditional stimulus were investigated in three dogs. At ...

The present study measured the effects of stimulus and reinforcer variations on pigeons' behavior in two different choice procedures. Two intensities of white light were presented as the stimuli on the main key in a switching-key concurrent schedule and as the sample stimuli in a signal-detection procedure. Under both procedures, ...

Three experiments showed the modulation of a rabbit eyeblink conditioned response (CR) to a Pavlovian conditioned stimulus (CS) by 30-s stimuli (A & B) that had been differentially paired with paraorbital shock. The CS (Y) was a 1,050-ms cue that had been paired with paraorbital shock outside A or B. ...

Allocation of responses between two keys was studied during two alternating multiple-schedule components. Responses were recorded in successive quarters of each component. Variable-interval reinforcer schedules on the two keys were constant throughout the experiment for one (constant) component and were varied over conditions on one key for the other, producing ...

1. The aversiveness of motion and noise to broiler chickens was examined using a passive avoidance technique. Birds were initially trained to peck a key a fixed number of times to obtain food. After training, food could still be obtained by key pecking, but feeding was immediately followed by 1 ...

The experiment reviewed here merges Garner's (1974) distinction of separable and integral stimulus properties with the field of Pavlovian eyelid conditioning with human subjects. According to one rule, two sets of stimuli (separable vs integral) were constructed. A differential compound conditioning procedure was used with one group of subjects being ...

Multiunit activity (MUA) was chronically recorded in the hippocampal CA3 field of rats using a blocking paradigm with conditioned suppression of lever pressing for food as the measure of conditioning. In Experiment 1, a classical blocking paradigm demonstrated the good conditionability of 2 stimuli (a light and a tone) and ...

The effects of different shaping approximations on the topography of the rat's bar press were investigated in two experiments. Behavior was classified into discrete components, and changes in components and their sequential organization were analyzed. Experiment 1 examined response form early in training and found that specific components reinforced during ...

The delay-reduction hypothesis of conditioned reinforcement states that the reinforcing value of a food-associated stimulus is determined by the delay to primary reinforcement signaled by the onset of the stimulus relative to the average delay to primary reinforcement in the conditioning situation. In contrast, most contemporary models of conditioned reinforcement ...